args = {...}
initY = args[1] - 1
targetY = args[2]

for y=initY, targetY, -1 do
    turtle.digDown()
    turtle.down()
    turtle.dig()
end

turtle.digDown()
turtle.down()
turtle.dig()
turtle.select(3)
turtle.place()
turtle.up()
turtle.select(4)
turtle.placeDown()

turtle.select(1)

for y=targetY, initY, 1 do
    turtle.place()
    turtle.up()
end